import 'package:flutter/material.dart';
import 'package:math_expressions/math_expressions.dart';

class FikoYTFinansalKlavye extends StatefulWidget {
  final Function(String) onInput;
  final Function(double?) onCalc;
  final Function() onDelete;

  const FikoYTFinansalKlavye({
    required this.onInput,
    required this.onCalc,
    required this.onDelete,
    super.key,
  });

  @override
  State<FikoYTFinansalKlavye> createState() => _FikoYTFinansalKlavyeState();
}

class _FikoYTFinansalKlavyeState extends State<FikoYTFinansalKlavye> {
  String _input = "0.0";
  final List<String> _history = [];
  int _historyIndex = -1;
  String _currency = "";
  bool _soundEnabled = true;
  final double _fontSize = 16;

  void _handleInput(String value) {
    setState(() {
      if (value == '=') {
        _calculateResult();
      } else {
        _input += value;
      }
      _history.add(_input);
      _historyIndex = _history.length - 1;
    });
    _triggerHapticFeedback();
    if (_soundEnabled) _playSound();
    widget.onInput("$_input $_currency");
  }

  void _calculateResult() {
    try {
      _input = _evaluateExpression(_input);
      widget.onCalc(double.tryParse(_input));
    } catch (e) {
      _input = "Hata";
      widget.onCalc(null);
    }
  }

  String _evaluateExpression(String expression) {
    try {
      expression = expression.replaceAll('×', '*').replaceAll('÷', '/');
      return _safeEval(expression).toString();
    } catch (e) {
      return "Hata";
    }
  }

  double _safeEval(String expr) {
    ExpressionParser p = GrammarParser();
    Expression exp = p.parse(_input);
    ContextModel cm = ContextModel();
    double eval = exp.evaluate(EvaluationType.REAL, cm);
    return eval;
  }

  void _handleDelete() {
    setState(() {
      if (_input.isNotEmpty) {
        _input = _input.substring(0, _input.length - 1);
        _history.add(_input);
        _historyIndex = _history.length - 1;
      }
    });
    _triggerHapticFeedback();
    widget.onDelete();
  }

  void _handleUndo() {
    if (_historyIndex > 0) {
      setState(() {
        _historyIndex--;
        _input = _history[_historyIndex];
      });
    }
  }

  void _handleRedo() {
    if (_historyIndex < _history.length - 1) {
      setState(() {
        _historyIndex++;
        _input = _history[_historyIndex];
      });
    }
  }

  void _toggleCurrency() {
    setState(() {
      List<String> currencies = ['₺', '\$', '€', '£'];
      int currentIndex = currencies.indexOf(_currency);
      _currency = currencies[(currentIndex + 1) % currencies.length];
    });
  }

  void _toggleSound() {
    setState(() {
      _soundEnabled = !_soundEnabled;
    });
  }

  void _triggerHapticFeedback() {}

  void _playSound() {}

  @override
  Widget build(BuildContext context) {
    return LayoutBuilder(
      builder: (context, constraints) {
        // double aspectRatio = constraints.maxHeight > 10
        //     ? constraints.maxWidth / (constraints.maxHeight / 5)
        //     : 1;
        return Container(
          padding: const EdgeInsets.all(0.0),
          decoration: BoxDecoration(
            // color: Colors.grey[200],
            borderRadius: BorderRadius.circular(0),
          ),
          child: GridView.builder(
            shrinkWrap: true,
            physics: const NeverScrollableScrollPhysics(),
            gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
              crossAxisCount: 4,
              childAspectRatio: (1 / .7),
              // childAspectRatio: aspectRatio,
            ),
            itemCount: 20,
            itemBuilder: (context, index) {
              List<String> keys = [
                '7',
                '8',
                '9',
                '/',
                '4',
                '5',
                '6',
                '*',
                '1',
                '2',
                '3',
                '-',
                '0',
                '.',
                'C',
                '+',
                '(',
                ')',
                '=',
                '<'
              ];
              return GestureDetector(
                onTap: () {
                  if ((_input == "Hata") || (_input == "0.0")) {
                    _input = "";
                  }
                  if (keys[index] == 'C') {
                    setState(() => _input = "0.0");
                    widget.onInput("$_input $_currency");
                  } else if (keys[index] == '<') {
                    _handleDelete();
                    widget.onInput("$_input $_currency");
                  } else {
                    _handleInput(keys[index]);
                  }
                  if ((_input == "")) {
                    _input = "0.0";
                    widget.onInput("$_input $_currency");
                  }
                },
                child: Container(
                  margin: const EdgeInsets.all(1.0),
                  decoration: BoxDecoration(
                    color: Colors.white,
                    borderRadius: BorderRadius.circular(0),
                    boxShadow: [
                      // BoxShadow(
                      //   color: Colors.black26,
                      //   blurRadius: 1,
                      //   spreadRadius: 1,
                      // ),
                    ],
                  ),
                  alignment: Alignment.center,
                  child: Text(
                    keys[index],
                    style: TextStyle(
                      fontSize: _fontSize,
                      fontWeight: FontWeight.bold,
                    ),
                  ),
                ),
              );
            },
          ),
        );
      },
    );
  }
}